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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Similarities between the metabolic syndrome and Cushing's syndrome, and reversibility of the features of Cushing's syndrome, suggest that cortisol may contribute to the pathophysiology of both conditions and that reducing cortisol action may provide a novel therapeutic approach in the metabolic syndrome. There is substantial evidence that circulating cortisol concentrations are higher in people with hypertension and glucose intolerance. The basis for this activation of the hypothalamic-pituitary-adrenal axis remains uncertain, but it may be attributable to 'programming' effects of events in early life, since it is associated with low birth weight. In obese people, intracellular cortisol levels within adipose tissue are further amplified by increased local regeneration of cortisol by the enzyme 11beta-HSD type 1. In mice, transgenic manipulations of 11beta-HSD1 have potent effects on obesity and associated features of the metabolic syndrome. Promising preclinical data suggest that novel 11beta-HSD1 inhibitors will have a role in lowering intracellular cortisol levels as a treatment for the metabolic syndrome. In addition to their metabolic effects, glucocorticoids act in the blood vessel wall. Pharmacoepidemiological studies suggest that glucocorticoid excess is an independent risk factor for cardiovascular disease. Recent data suggest that 11beta-HSD1 within the blood vessel wall influences vascular remodelling and angiogenesis, for example in the myocardium following coronary artery occlusion. Thus, glucocorticoid signalling provides a potentially tractable system to influence both risk factors for, and the outcome of, Type 2 diabetes and cardiovascular disease.
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PMID:Cortisol--cause and cure for metabolic syndrome? 1711 76

The major glucocorticoid in man, cortisol, plays important roles in regulating fuel metabolism, energy partitioning and body fat distribution. In addition to the control of cortisol levels in blood by the hypothalamic-pituitary-adrenal axis, intracellular cortisol levels within target tissues can be controlled by local enzymes. 11Beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) catalyses the regeneration of active cortisol from inert cortisone, thereby amplifying cortisol levels and glucocorticoid receptor activation in adipose tissue, liver and other tissues. 11Beta-HSD1 is under complex tissue-specific regulation and there is evidence that it adjusts local cortisol concentrations independently of the plasma cortisol concentrations, e.g. in response to changes in diet. In obesity 11beta-HSD1 mRNA and activity in adipose tissue are increased. The mechanism of this up-regulation remains uncertain; polymorphisms in the HSD11B1 gene have been associated with metabolic complications of obesity, including hypertension and type 2 diabetes, but not with obesity per se. Extensive data have been obtained in mice with transgenic over-expression of 11beta-HSD1 in liver and adipocytes, targeted deletion of 11beta-HSD1, and using novel selective 11beta-HSD1 inhibitors; these data support the use of 11beta-HSD1 inhibitors to lower intracellular glucocorticoid levels and treat both obesity and its metabolic complications. Moreover, in human subjects the non-selective 'prototype' inhibitor carbenoxolone enhances insulin sensitivity. Results of clinical studies with novel potent selective 11beta-HSD1 inhibitors are therefore eagerly awaited. The present article focuses on the physiological role of glucocorticoids in regulating energy partitioning, and the evidence that this process is modulated by 11beta-HSD1 in human subjects.
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PMID:Extra-adrenal regeneration of glucocorticoids by 11beta-hydroxysteroid dehydrogenase type 1: physiological regulator and pharmacological target for energy partitioning. 1734 66

Deficiencies in the conversion between active and inactive glucocorticoids in the kidney can lead to hypertension. However, the significance of glucocorticoid metabolism in specific kidney regions in vivo is not clear, possibly in part due to the difficulty in measuring glucocorticoid levels in kidney regions in vivo. We used microdialysis techniques to sample renal interstitial fluid from conscious rats. The levels of corticosterone (active) and 11-dehydrocorticosterone (inactive) were analyzed by liquid chromatography-tandem mass spectrometry. Direct infusion of the 11beta-hydroxysteroid dehydrogenase (11beta-HSD) inhibitor carbenoxolone into the renal medulla induced hypertension, and significantly increased corticosterone levels and the corticosterone/11-dehydrocorticosterone ratio, an index of 11beta-HSD activity, in the renal medullary microdialysate, but not in urine or the plasma. Further characterization of conscious, untreated rats (n = 13-16) indicated that corticosterone concentrations (ng/ml) were 0.8 +/- 0.1, 1.0 +/- 0.1, 66.7 +/- 8.1, and 7.9 +/- 1.1 in cortical microdialysate, medullary microdialysate, the plasma, and urine, respectively. The corticosterone/11-dehydrocorticosterone ratios were 0.8 +/- 0.1, 0.6 +/- 0.1, 10.6 +/- 1.4, and 1.7 +/- 0.1, respectively, in these 4 types of sample. The expression level of 11beta-HSD1 was higher in the medulla than in the cortex, whereas 11beta-HSD2 was most enriched in the outer medulla. Microdialysate levels of corticosterone were approximately 1.6-fold higher in afternoons than in mornings, whereas plasma levels differed by 2.8-fold. These results demonstrated that corticosterone excess in the renal medulla might be sufficient to cause hypertension and provided the first characterization of renal interstitial glucocorticoids.
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PMID:Renal interstitial corticosterone and 11-dehydrocorticosterone in conscious rats. 1738 75

Proopiomelanocortin (POMC) deficiency causes severe obesity through hyperphagia of hypothalamic origin. However, low glucocorticoid levels caused by adrenal insufficiency mitigate against insulin resistance, hyperphagia and fat accretion in Pomc-/- mice. Upon exogenous glucocorticoid replacement, corticosterone-supplemented (CORT) Pomc-/- mice show exaggerated responses, including excessive fat accumulation, hyperleptinaemia and insulin resistance. To investigate the peripheral mechanisms underlying this glucocorticoid hypersensitivity, we examined the expression levels of key determinants and targets of glucocorticoid action in adipose tissue and liver. Despite lower basal expression of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1), which generates active glucocorticoids within cells, CORT-mediated induction of 11beta-HSD1 mRNA levels was more pronounced in adipose tissues of Pomc-/- mice. Similarly, CORT treatment increased lipoprotein lipase mRNA levels in all fat depots in Pomc-/- mice, consistent with exaggerated fat accumulation. Glucocorticoid receptor (GR) mRNA levels were selectively elevated in liver and retroperitoneal fat of Pomc-/- mice but were corrected by CORT in the latter depot. In liver, CORT increased phosphoenolpyruvate carboxykinase mRNA levels specifically in Pomc-/- mice, consistent with their insulin-resistant phenotype. Furthermore, CORT induced hypertension in Pomc-/- mice, independently of adipose or liver renin-angiotensin system activation. These data suggest that CORT-inducible 11beta-HSD1 expression in fat contributes to the adverse cardiometabolic effects of CORT in POMC deficiency, whereas higher GR levels may be more important in liver.
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PMID:Peripheral mechanisms contributing to the glucocorticoid hypersensitivity in proopiomelanocortin null mice treated with corticosterone. 1759 30

Population-based studies have shown that the offspring of diabetic mothers have an increased risk of developing obesity, insulin resistance, type 2 diabetes and hypertension in later life. To investigate mechanism for the high incidence of metabolic diseases in the offspring of diabetic mothers, we focused on the tissue-specific glucocorticoid regulation by 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) and studied offspring born to streptozotocin-induced diabetic rats. The body weights of newborn rats from diabetic mothers were heavier than those from control mothers. Offspring born to diabetic mothers demonstrated insulin resistance and mild glucose intolerance after glucose loading at 10 weeks and showed significantly increased 11beta-HSD1 mRNA and enzyme activity in adipose tissue at 12 weeks of age without obvious obesity. Hepatic 11beta-HSD1 mRNA was also elevated. We propose that the 11beta-HSD1 in adipose tissue and liver may play a key role in the development of metabolic syndrome in the offspring of diabetic mothers. Tissue-specific glucocorticoid dysregulation provides a candidate mechanism for the high incidence of metabolic diseases in the offspring of diabetic mothers. Therefore early analyses before apparent obesity are needed to elucidate the molecular mechanisms that may be programmed during the fetal period.
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PMID:Diabetic pregnancy in rats leads to impaired glucose metabolism in offspring involving tissue-specific dysregulation of 11beta-hydroxysteroid dehydrogenase type 1 expression. 1769 75

The 11beta-hydroxysteroid dehydrogenase (11beta-HSD) exists in two isoforms, 11beta-HSD1 and 11beta-HSD2. 11beta-HSD1 generates active cortisol from cortisone and appears to be involved in insulin resistant states. 11beta-HSD2 protects the mineralocorticoid receptor from inappropriate activation by glucocorticoids and is important to prevent sodium retention and hypertension. The purposes of the present study were to develop two real-time PCR assays to assess 11beta-HSD1 and 11beta-HSD2 mRNA expression and to evaluate the tissue distribution of the two isoforms in dogs. Thirteen different tissues of 10 healthy dogs were evaluated. Both real-time PCR assays were highly specific, sensitive and reproducible. Highest 11beta-HSD1 mRNA expression was seen in liver, lung, and renal medulla; highest 11beta-HSD2 mRNA expression in renal cortex, adrenal gland, and renal medulla. Higher 11beta-HSD1 than 11beta-HSD2 mRNA levels were found in all tissues except adrenal gland, colon, and rectum. Our results demonstrate that the basic tissue distribution of 11beta-HSD1 and 11beta-HSD2 in dogs corresponds to that in humans and rodents. In a next step 11beta-HSD1 and 11beta-HSD2 expression should be assessed in diseases like obesity, hypercortisolism, and hypertension to improve our knowledge about 11beta-HSD activity, to evaluate the dog as a model for humans and to potentially find new therapeutic options.
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PMID:Quantitative real-time PCR for the measurement of 11beta-HSD1 and 11beta-HSD2 mRNA levels in tissues of healthy dogs. 1771 18

Central obesity is associated with type 2 diabetes mellitus, hypertension and dyslipidaemia. This cluster of risk factors is known as the metabolic syndrome, and also occurs in people with primary glucocorticoid excess (Cushing's syndrome). Exogenous glucocorticoid use also increases the risk of cardiovascular disease. Circulating glucocorticoid concentrations are tightly controlled by the hypothalamic-pituitary-adrenal axis, however tissue glucocorticoid levels are also enhanced by the enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1). Transgenic overexpression of 11beta-HSD1 in either adipose tissue or the liver in mice causes components of the metabolic syndrome, while transgenic deletion of 11beta-HSD1 prevents adverse metabolic complications of obesity. Although plasma glucocorticoid levels are not elevated in obesity, dysregulation of 11beta-HSD1 is observed with decreased activity in the liver and increased activity in adipose tissue. 11beta-HSD1 is highly regulated, and dietary composition may be a powerful determinant of activity. Polymorphisms in the 11beta-HSD1 gene are also associated with components of the metabolic syndrome. Inhibition of this enzyme appears to be an attractive option to treat metabolic disease. Selective 11beta-HSD1 inhibitors in rodents cause weight loss, improve insulin sensitivity and delay progression of cardiovascular disease. Trials in humans though will be the ultimate test to determine if inhibition of 11beta-HSD1 offers a new tool in the treatment of metabolic disease.
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PMID:Glucocorticoids and 11beta-hydroxysteroid dehydrogenase type 1 in obesity and the metabolic syndrome. 1791 54

11beta-Hydroxysteroid dehydrogenase (11beta-HSD) type 1 and type 2 catalyze the interconversion of inactive and active glucocorticoids. Impaired regulation of these enzymes has been associated with obesity, diabetes, hypertension, and cardiovascular disease. Previous studies in animals and humans suggested that dehydroepiandrosterone (DHEA) has antiglucocorticoid effects, but the underlying mechanisms are unknown. In this study, DHEA treatment markedly increased mRNA expression and activity of 11beta-HSD2 in a rat cortical collecting duct cell line and in kidneys of C57BL/6J mice and Sprague-Dawley rats. DHEA-treated rats tended to have reduced urinary corticosterone to 11-dehydrocorticosterone ratios. It was found that CCAAT/enhancer-binding protein-alpha (C/EBP-alpha) and C/EBP-beta regulated HSD11B2 transcription and that DHEA likely modulated the transcription of 11beta-HSD2 in a phosphatidylinositol-3 kinase/Akt-dependent manner by increasing C/EBP-beta mRNA and protein expression. Moreover, it is shown that C/EBP-alpha and C/EBP-beta differentially regulate the expression of 11beta-HSD1 and 11beta-HSD2. In conclusion, DHEA induces a shift from 11beta-HSD1 to 11beta-HSD2 expression, increasing conversion from active to inactive glucocorticoids. This provides a possible explanation for the antiglucocorticoid effects of DHEA.
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PMID:DHEA induces 11 -HSD2 by acting on CCAAT/enhancer-binding proteins. 1803 97

The metabolic syndrome consists of a constellation of co-associated metabolic abnormalities such as insulin resistance, type 2 diabetes, dyslipidaemia, hypertension and visceral obesity. For many years endocrinologists have noted the striking resemblance between this disease state and that associated with Cushing's syndrome. However, in the metabolic syndrome plasma cortisol levels tend to be normal or lower than in normal individuals. Nevertheless there is strong evidence that glucocorticoid action underlies metabolic disease, largely from rodent obesity models where removing glucocorticoids reverses obesity and its metabolic abnormalities. The apparent paradox of similar metabolic defects - despite the opposing plasma glucocorticoid profiles of Cushing's and idiopathic metabolic syndrome - remained intriguing until the discovery that intracellular glucocorticoid reactivation was elevated in adipose tissue of obese rodents and humans. The enzyme that mediates this activation, conversion of cortisone (11-dehydrocorticosterone in rodents) to cortisol (corticosterone in rodents), locally within tissues is 11beta -hydroxysteroid dehydrogenase type 1 (11beta -HSD1). In order to determine whether elevated tissue 11beta -HSD1 contributed to obesity and metabolic disease, transgenic mice overexpressing 11beta -HSD1 in adipose tissue or liver were made. Adipose-selective 11beta -HSD1 transgenic mice exhibited elevated intra-adipose and portal, but not systemic corticosterone levels, abdominal obesity, hyperglycaemia, insulin resistance, dyslipidaemia and hypertension. In contrast, transgenic overexpression of 11beta -HSD1 in liver yielded an attenuated metabolic syndrome with mild insulin resistance, dyslipidaemia, hypertension and fatty liver, but not obesity or glucose intolerance. Together with early data using non-selective 11beta -HSD1 inhibitors to insulin sensitise humans, this corroborated the notion that the enzyme may be a good therapeutic target in the treatment of the metabolic syndrome. Further, a transgenic model of therapeutic 11beta -HSD1 inhibition, 11beta -HSD1 gene knock-out (11beta -HSD1-/-) mice, exhibited improved glucose tolerance, a 'cardioprotective' lipid profile, reduced weight gain and visceral fat accumulation with chronic high-fat feeding. Recent evidence further suggests that high fat-mediated downregulation of adipose 11beta -HSD1 may be an endogenous pathway that underpins adaptive disease resistance in genetically predisposed mouse strains. This mechanism could feasibly make up a genetic component of innate obesity resistance in humans. The efficacy of 11beta -HSD1 inhibitors has recently been extended to include increased energy expenditure and reduction of arteriosclerosis, and therefore may be of significant therapeutic value in the metabolic syndrome, with complementary effects upon liver adipose tissue, muscle, pancreas and plaque-prone vessels.
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PMID:11beta-hydroxysteroid dehydrogenase type 1 and obesity. 1823 Sep 1

The metabolic syndrome is a constellation of interrelated metabolic risk factors that appear to promote the development of diabetes and cardiovascular disease. These risk factors include abdominal obesity, insulin resistance, hypertension and dyslipidemia. 11beta-Hydroxysteroid dehydrogenase (11beta-HSD) catalyzes the interconversion of glucocorticoids through the activity of two isozymes: type 1 (11beta-HSD1) and type 2 (11beta-HSD2). 11beta-HSD1 converts inactive glucocorticoid to the active form, whereas 11beta-HSD2 converts active glucocorticoid to the inactive form. It is well established that reduced 11beta-HSD2 activity causes hypertension and electrolyte abnormalities. More recently, the pathophysiological role of 11beta-HSD1 has been explored and studies suggest that increased 11beta-HSD1 activity within target tissues may promote insulin resistance, obesity, hypertension and dyslipidemia. This review will discuss the evidence that inhibition of 11beta-HSD1 may be therapeutic in the treatment of the metabolic syndrome.
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PMID:11beta-hydroxysteroid dehydrogenase type 1 inhibitors for metabolic syndrome. 1831 66


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